I. Field of the Invention
The present invention generally relates to the field of medical devices. More specifically, the present invention relates to support catheters that can be manipulated to track through vessels of the body as well as through obstructions in such vessels.
II. Related Technology
The use of intravascular devices to treat cardiovascular diseases is well known in the field of medicine. The need for a greater variety of devices to address different types of circumstances has grown tremendously as the techniques for using intravascular devices has progressed. One type of intravascular device is a catheter. Typically, an intravascular catheter is delivered into the body by first using a support catheter that can be routed through the proper vessels in the body's vascular network in order to arrive at a site in need of a diagnostic or therapeutic technique.
Previously, support catheters have been relatively simple and have been made of biocompatible plastics forming a shaft with a hollow internal lumen. The shaft is generally formed by one or more concentric tubes that are congruent to each other, where one tube typically provides support and the other tube(s) provide biocompatibility. Additionally, most support catheters include a hub that is connected to a proximal end of the shaft in order to provide a mechanism for connecting another device, such as an inflation device or syringe, and in order to provide a means to direct a subsequent guidewire through the support catheter into the vessel to the desired location for treatment or diagnostics. Usually, the tip of the support catheter is flexible and/or shaped in order to allow for deployment and placement in the tortuous vasculature network.
In order for a medical professional to insert the catheter into the proper location in the vessel, longitudinal and rotational forces applied to the support catheter must be translated to the distal end on the tip of the support catheter. This enables the medical professional to maneuver the distal end of the support catheter through various bends, junctions, or features of vessels in the vasculature. The tip of the support catheter can be soft and flexible to prevent damage to the vasculature as the support catheter is pushed or advanced therethrough. As such, the existing support catheters are stiff enough to be advanced through a blood vessel, yet include the flexible tip to aid with guiding the catheter through or around various bends or junctions.
The treatment of chronic total occlusions (“CTOs”) has raised even further challenges to accessing both sides of the CTO. A CTO is a chronic problem that developed into a total obstruction or blockage in a vessel. The composition of a CTO may be classified as hard plaque, soft plaque or a mixture of the two. Percutaneous intervention is a minimally invasive way to treat vessels having CTOs and is accomplished with conventional guidewire techniques, e.g., slowly advancing the guidewire through the CTO to obtain the desired access to deploy balloon, stents, or other medical devices. As set forth above, catheters often are used to provide support to the guidewire.
In many cases, there is a cap with a calcified lesion at the proximal side of the occlusion (the “proximal cap”), where the blood flow is obstructed at the occlusion. It can be very difficult to advance a guidewire through this proximal cap to penetrate the CTO unless one can maneuver a guidewire or device through it. There are micro channels that run through the CTO. These micro channels may aid the medical professional in being able to maneuver a guidewire through a CTO. Crossing the proximal cap with a guidewire or other device or exploiting the micro channels, is a goal in recanalizing a vessel since it facilitates clearing the occlusion from the vessel.
It would be advantageous to have a support catheter that has the properties of flexibility and rigidity that further aid in maneuvering a guidewire through the CTO. More particularly, it would be advantageous to have a support catheter that can track to the site of a vessel occlusion, such as a CTO, and provide sufficient support to aid the guidewire to cross the occlusion.